Propelling mechanism



July 7, 1931.

J. STECHAUNER 1,813,552

PROPELLING ME CHANI SM Filed April 2, 0

Patented July 7, 1931 UNITED STATES PATENT OFFICE i I JOHN STECI-IAUNER, F MILWAUKEE, WVISUON SIN, ASSIGNOR OF ONE-SIXTH TO JOHN I-IAAS AND ONE-SIXTH TO GABRIEL GOETZ, BOTH 0J3 MILWAUKEE, WISCONSIN" PROPELLING MECHANISM Application filed April 2, 1930. Serial; No. 441,006.

whereby the efficiency of the propelling unit may be greatly increased with only a small expenditure of additional energy. More particularly, the invention consists in the association of two propellers of substantially the same size and of opposite pitch mounted adjacent each other, each on a drive shaft arranged concentric to and driven in the opposite direction to the other shaft.

The invention further consists in the several features hereinafter set forth and more particularly defined by claims at the conclusion hereof.

In the drawings Fig. 1 is an elevation view of an outboard motor equipped with propelling mechanism embodying the invention;

Fig. 2 is a detail vertical, sectional view through the propelling mechanism;

Fig. 3 is a detail sectional view taken on the line 33 of Fig. 2;

Referring to Figs. 1 to 3, inclusive, the numeral 6 designates a rowboat, 7 an outboard motor secured thereto in known man- :a ner, embodying the usual engine suitably connected to drive the vertically disposed transmission shaft 8 suitably journalled in the casing 9.

The shaft 8 carries a bevel gear 10 meshing with oppositely disposed bevel gears 11 and 12, respectively fixed to propeller shafts 13 and 14, the shaft 1st being hollow and journalled in a bearing portion. 15 of the casing, while the shaft 13 is journalled at one end 16 in the casing and extends through and is rotatably mounted within the hollow shaft 14. Thus the shafts 13 and 14 are concentrically mounted and because of the gearing above described are driven in opposite directions and at the same speed.

The shaft ll has a propeller 17 mounted thereon against a shoulder 18 and securely clamped thereto by a nut 19 on the threaded end of said shaft.

The shaft 13 has a propeller 20 mounted thereon to rotate therewith in any suitable manner, as by means of clamping nuts21 and 22.

The propellers 17 and 20 are of substantially the same pitch ratio, but of opposite pitch and of substantially the same size.

The gear ratio of the drive mechanism above described is unity, so that the pro pellers 17 and 20 are driven at substantially the same speed.

It will be observed that the two oppositely revolving propeilers are mounted adjacenteach other so that the first propeller forces the water or air against the other so that the second propeller can act with more force thereon. That this action does occur has been demonstrated by trials of a-device embodying the invention, wherein it has been found that for an additional expenditure of energy of only one and four-tenths per cent over that required to drive one propeller, I obtain almost one-third more tractive effort by the use of thetwo over a single propeller. Thus, it will be understood that the propellers are arranged close enough together that the reactive componcuts of one are within the range of action of the other and where the pitch of the propellers is great, the propellers should be ar-' ranged more closely together than where the pitch is smaller, since with the greater pitch the water or air streams againstwhich the the second propeller works are shorter than those where the pitch is less. In the use of these two propellers it will be observed that the first propellerovercomes the inertia or the resistance of the mass in which the propeller is working and that the second propeller is, therefore, substantially relieved of this duty and bores its Way through the stream or immediate wake of the first propeller.

While the two-blade propellers have been shown, it is obvious that three or more blades may be used on the propellers for larger craft and while an outboard motor is shown, it is obvious that the invention may be applied to other forms of marine propulsion apparatus without departing from the spirit of this invention.

I, therefore, desire it to be understood that this invention is not to be limited to any particular form or arrangement of parts except insofar as such limitations are 5 included in the claim.

lVhat I claim as my invention is:

In a propelling mechanism, the combine tion with an underwater housing, of a power transmission shaftjournalled in said housing andextending lengthwise" thereof and provided with a bevel gear, a sleeve shaft extending at right anglesto said first; named shaft and journalled in one end of said housing and provided with a' bevel gear;

meshing With said first named gear and having a shoulder exterior of said housing,- a propeller mounted on said second sleeve shaft and abutting said shoulder, athird shaft extending atri'ght angles to said first shaft and journa'lled in said housing and extending through said sleeve shaft provided with a bevel gear meshing with said first named bevel gear, and a propeller mounted on the outer end of said third shaft, said propellers being of substantially similar pitch ratio and size but of opposite pitch and mounted adjacent each other, saidsecond and third named bevelv gears being disposed on opposite sides of said first named bevel gear and being of the same pitch diameter.

In testimony whereof, I aflix my signa ture;

JOHN STECHAUNER. 

